Manufacture of viscous water-white oils and other decolorized products of petroleum



UNITED STATES PATENT OFFICE.

ERNEST B. COBB, OE JERSEY CITYhNEW JERSEY, ASSIGNOB TO STANDARD OIL COM- PANY, 0F BAYONNE, NEW JERSEY;

A conronanon or NEW JERSEY.

MANUFACTURE OF VISCOUS WATER-WHITE ,OILS AND OTHER DECOLORIZED PROD-- UCTS 'OF PETROLEUM.

No Drawing. Application filed July 23,

T 0 all whom it may) concern:

Be it known that I, ERNEST B. C oBB, a citizen of the United States, reslding at Jersey City, in the county of Hudson and State of New Jersey, have invented certain mercial grade of water white and whose component hydrocarbons (for the most part at least) are higher in viscosity (as well as in boiling point) than the highest boiling of those normal to burning oil (kerosene) but,

as will hereinafter more fullv appear, the

invention is not wholly limited to such manufacture. The highest boiling hydrocarbons normal to burning oil (kerosene) are considered to distil over from a laboratory flask at about 572 F. (vapor temperature) and the most viscous hydrocarbons normal thereto are considered to have viscosities of about forty seconds at 100 F. by a Saybolts Universal viscosimeter. An equal volume of water will pass through such viscosimeter inv thirty one seconds at F. All the viscosities stated herein are to be determined by the same viscosimeter. The slightly colored liquid which results from first dissolving one tenth gram of potassium chromate (11 C10 in one liter of distilled water and then diluting say five cubic centimeters of this solution to one hundred cubic centimeters with distilled water is considered to have about the maximum of color permissible in burning oil (kerosene) of the commercial grade of water white/ 'hite oils havebeen used medicinally (in one mode at least by being taken into the stomach through the mouth) and also industrially (in one mode at least by being mixed with vegetable oil in the manufacture of soap). They have chiefly. it is believed, been products of Russian petroleum. Viscous Russian distillate is more easily decolor- Specification of Letters Patent. Patented Aug. 23, 1921.

1914. Serial in. 852,671.

ized than Pennsylvania distillate of the same viscosity.

In accordance with the present invention (portions of which can be used separately) a suitable white oil stock is subjected to the action of sulfuric acid so 'as to form an acid sludge which is removed; the acid treated oil is distilled with use of special agency,

such as injection of dry steam into the oil in distillation, to prevent (or restrict) the decomposition (cracking) of" component hydrocarbons: the so obtained distillate is subjectedto the action of sulfuric acid so as to form an acid sludge which is removed; and the oil, which has thus been twice subjected to the action of sulfuric acid and to a special intervening distillation, is filtered through solid decolorizing material, such as Florida clay, a material well known in petroleum refineries.

In this process part of the coloring matter of the'stock is removed directly (that isto say, in the form of sludge) by the first acid treatment, and another part is so altered thereby as to become decomposable in p the subsequent distillation of the acid treated oil, notwithstanding the employment of special agency (as aforesaid) to prevent (or restrict) decomposition (cracking) in said distillation: while the second treatment with sulfuric acid removes colored substances some of which are no doubt formed in said distillation, but some of which may be unaltered constituents of the original stock;

and the thus twice treated interveningly distilled oil is then further decolorized by the filtration. The sulfuric acid'in each of the treatments therewith, moreover. it is believed, so alters some of the coloring matter as to make it more susceptible to removal by subsequent filtration of the oil than it otherwise would be; and saidfiltration may remove some unaltered coloring matter of the original stock. as well as colored substances produced-by the action of one or more of the preceding operations on original (colored or uncolored) constituents of the stock.

In carrying out the process the following special features may well be employed.

First. The stock operated upon may well be obtained as distillate in a distillation in which special agency is employed to prenot more than about ten degrees B. heavier.

Third. The stock operated upon may well consist (even when composed; as just mentioned, of hydrocarbons within a comparatively narrow range of ravity) of a certain percentage which (consistently with the obtainment of the desired white oil) can be.

rejected after the earlier of the treatments with sulfuric acid at the beginning of the succeeding special distillation.

Fourth. The stock may well have about the viscosity desired in the finished oil, neither largely (if at all) more viscous nor largely (if at all) less viscous than the finished oil to be obtained therefrom.

Fifth. The stock may well contain only a small percentage (if any) of hydrocarbons too viscous to be desirable ingredients in the finished oil to be obtained from said stock.

Sixth. Stronger acid than commercial acid of 1.835 specific gravity (which ordinarily contains and which is iegarded herein as containing about 92.5% to 93% by weight of sulfuric monohydrate H SO and .about 7% to 7.5% of water) may well be employed in each of the treatments with drate.

sulfuric acid. Sulfuric anhydrid S0 is regarded herein as one form of such stronger acid. as well as fuming sulfuric .acid of all strengths and non-fuming acid which contains in excess of 93% sulfuric monohy- Good results have been obtained with fuming sulfuric acid containing twenty parts by weight of sulfuric anhydrid and eighty parts by weight of sulfuric monohy= 5 geticthan the later of them (as by using drate. the same being'a commercial article and being referned to hereinafter as 20% fuming sulfuric acid.

Seventh. The initial temperature for each of the treatments with sulfuric acid may well be not higher than about F...say between about 70 F. and about 20 F., and even lower, if desired {and it is believed that improvement would result from each lowering of said initial temperature from 70 F. downward to at least as low as 20 F. The chemical reactionstend to raise the temperature. Special cooling to restrict such rise is consideredunnecessary; but the use of'the same is not necessarily excluded.

E1ghth. The earlier of the treatments with sulfuric acid may well be more enertling.

a larger proportion of sulfuric acid of given strength, or the same proportion of a stronger acid, or both a lar r proportion and a greater strength of acid in the earlier than in the later treatment).

Ninth. The acidity of the oil after the earlier of the treatments with sulfuric acid may well be neutralized with alkaline material (as caustic soda lye) prior to distillation.

Tenth. Acid treated stock which contains onlv a small percentage (if any) of hydrocar ns too viscous to be desirable ingredients in the finished oil to be obtained from said stock may well be distilled approximately at least to dryness; and. inasmuch as in distilling with injection of dry steam (or of any aeriform fluid) into the oil in distillation there must always be enough material in the still to cover the injecting pipes, resort may well be had to the hereinafter described mode of distilling with injection of aeriform fluid in order to distil the said acid treated stock to dryness or approximately so.

Eleventh. The stock which has been twice subjected to treatment with sulfuric acid and to the intervening distillation may well be filtered in an acid condition.

Twelfth. The so treated and interveningly distilled stock may well be filtered. throug solid decolorizin material which is partiall exhausted and a terward through that which is exhausted in less degree (if at all), the said material, after losing some of its original decolorizing power, being used in an earlier sta e of the filtration.

I hirteenth. The filtrate (filtered oil) may well be subjected to free steam under suci conditions of temperature and pressure that the steam in part condenses and in part passes off in aeriform condition, thus washing out those impurities which may be soluble in the hot water of condensation and carrying those away in aeriform condition which will volatilize.

Fourteenth. The amount of solid decolorizingmaterial necessary to a. given decolorizing effect, by the combined operation of the two treatments with sulfuric acid, the intervening special distillation and the subsequent filtration through said solid decolorizing material, would in general be less the more energetic the treatments with sulfuric acid; and conversely; but the changes are not in constant ratio; and it. isestimated that in making a water white oilof about eighty seconds viscosity at 100 F. it would under existing conditions be financially unprofitable to use on the one hand as. much as the equivalent (in content of sulfur trioxid in the form of sulfuric anhydrid or monohydrate, orv both) of twenty llons of 20% fuming sulfuric acid to the arrel of stock The spent lye is removed by setsubjected thereto, or, on the other hand, su1- furic acid treatments so little energetic that the equivalent (in decolorizing power) of more than three hundred pounds of freshly calcined Florida clay to the barrel of oil subjected to the filtering operation would be needed (after the two treatments with sulfuric acid and the intervening special distillation) in order to render the so filtered and subsequently steamed oil water white; and the amount of sulfuric acid (of appropriate strength) em loyed may well be kept within these limits i1? pbtaining a decolorized oil up to about eigh y seconds viscosity at 100 F., whatever type of petroleum may be operated upon, with permissible increases in the amounts mentioned of solid decolorizing material and of sulfuric acid respectively for de colorizing oil of higher viscosity.

i While, however, these special features, all and singular, ma well be used. at least in some cases. in per orming the general process aforesaid. if it should be preferred in any case to omit any one or more, or even all, of said features, such omission can be made within the limits of the invention. Thus the stock operated upon may be obtained otherwise than as distillate in a distillation in which special agency is employed to prevent decomposition of com onent hydrocarbons; its hydrocarbons may liave a wider range of gravities than ten degrees B. it may be practically free from hydrocarbons to be rejected at the beginning of the intervening special distillation: its viscosity need not be aboutthe same as that desired in the finished oil; it may contain more than a small percentage (as mentioned) of hydrocarbons too viscous to be desirable ingredients in the finished oil.

The use of sulfuric acid of 1.835 specific gravity (even acid of less stren th) instead of or in addition to stronger aci is not necessarily excluded ineither or in each of the treatments; nor is the use of temperatures above TO F. initial and the later of the two treatments with sulfuric acid may be as energetic as or more energetic than the earlier of them."

The acidity of the oil is not necessarily neutralized before the special distillation. thereof. -Where stock is used which contains con-' siderable' hydrocarbons which would be undesirable ingredients in the finished oil and are of sufliciently high boiling point to remain in the still to the close of the distillationQan appropriate undistilled residue may well be left in the still, insteadof distilling the stock to dryness or approximately so in said special distillation. The stock need not be filtered in acid condition. Xeutralization of acidity after the later treatment with sulfuric acid and prior to the filtration is not necessarily excluded. Filtration may be performed otherwise than inthe special manner mentioned. \Vashing of the filtrate (filtered tile impurities (one or other or both) can be performed otherwise than by injection thereinto of free steam under conditions of temperature and pressure at which partial condensation takes place of the injected steam; and the finishing of the oil in modes which (1 not involve such washing and evaporatim? (or either of them) is not necessarily'ex cluded. In fact. if the filtered oil should be satisfactory. it need not be further operated upon. The proportion of sulfuric acid and the proportion of solid decolorizing material are not necessarily either of them within the limits mentioned herein above.

Part of the specal features mentioned can be used (within the scope of the invention) otherwise than in performing the process mentioned.

An oil of about eighty seconds viscosity at 100 F. and having appreciably less color than the maximum permissible in burning oil of the commercial grade of water white has been obtained by using about six gallons (combined amount in the two treatments) of 20% fuming sulfuric acid per barrel (l0 gallons) of stock and about fifty five pounds of Florida clay to the barrel (-10 gallons) of oil subjected to the filtering operation: but it is anticipated that in large scale commercial working a similar oil can be obtained with smaller amounts of the two tilled residue) and other products (to he made from distillate) and the white oil stock being derived from a part of the distillate. This description is by way of example and illustration and is not intended to confine the invention thereto. Modifications within the scope of the invention can in fact be made indefinitely by addition. subtraction. substitution or otherwise so long as the substance is taken of any one or more of the claims at the close of this specification.

'The crude petroleum is distilled in an externally heated still with injection of dry steam into the oil in distillation. as customary in lubricating works: and a cut is made which will contain hydrocarbons of the viscosities desired in the white oil and which may well also be such as it would be desirable to make apart from the manufacture of whiteoil therefrom. say a cut between 39 B. and 34.5 B. (gravity of stream at the condenser outlet at beginning and end respectively of the cut). This particular cut v i would be reduced (with i or without prior oil) with hot water and evaporation of volachilling and pressing for paraflin wax, as

7 should have about the viscosity desired in the white oil to be made (last runnings say about 37 B. in gravity), dry steam being injected into the oil under reduction to fprewent decomposition. The residue would rm the white oil stock and may have a gravity of about 34 B. It is more homogeneous than a distillate collected in the crude oil run would be; although a cut-of distillate from the crude oil run can be used. Additional distillationscan, on the other hand, be made, if desired. The stock is cooled to a temperature of about 20F. (or as much below 70 F. as may be preferred) and is introduced into an agitator of the customary funnel bottomed upright cylindrical form until the desired charge has been received. The herein above mentioned 20% fuming sulfuric acid, also cooled to about 20 F. or as much below 70 F. as maybe preferred. is

' then supplied to the agitator in the proportion say of thirteen volumes of said acid to.

one hundred volumes of white oil stock. The oil and acid are agitated say with injected air (as customary in treating petroleum distillates with commercial sulfuric acid of 1.835 specific gravity) until the effect of the sulfuric acid is exhausted. The sludge is allowed to settle and is drawn oil". The acid treated oil is transferred to a clean agitator; and .its acidity is neutralized by agitation with any appropriate alkaline maf terial, say caustic soda lye, of 1.080 specific gravity. The spent alkali is allowed to set tle and is drawn off. The neutralized unenough neutralized oil to complete a new charge is run in. This new charge is distilled down to a 10% residue, as before Other charges are-simila rly formed until a charge is obtained'which can be distilled to dryness, or nearly so, and yet leave sufficient residue to cover the steam injecting pipes. This residue (amounting to about one or two per cent. by volume of the ag- 'gregated still charges) is removed to be disposed of as may bepreferred; and the still is further cleaned. if necessary, for the next run. Residues can be accumulated in other.

ways for distillation later to dryness, or

' nearly so. Neutralized unwashed oil can be charge has been distilled. off to-the tem-- porarily desired extent. The residue left by each of a number of runs could be withdrawn and stored until enough should ac-' cumulate to make a still charge; whereupon the accumulated residues could be charged into a still and distilled down to dryness, or nearly so. Yet other modes could be employed.

In distilling the acid treated oil (suitably the p esent example this undesirable'distillate ay amountto about fourteen per cent. by vo ume of-- the oil subjected to the distillation; and all the rest of the distillate is utilized.

By excluding a certain portion of the distillate, the advantage is gained of making the utilized distillate more homo neous without any extra distillation for t e purpose, a double function b'eing thus performed y the cue distillation. Onthe other hand, by minimizing the exclusions sulfuric acid is economized in the first treatmenttherewith. The desirable distillate, amounting to about eighty six per cent. of the tota obtained in this example, is agitated with say three r cent. by volume of the aforesaid 20% uming sulfuric acid, and se arated from the slud e by settling and rawing off the latter. his three per cent. would be about two per cent.- of the white oil stock (or eight-tenths of a gallon of the sulfuric or washing. It could, however, be neutralized, if preferred; but the acidity of the oil is found to assist the filterin operation. Florida clay which has been fres ily calcined would best be used.

The filtrate is steamed until it is considered by the operator to be odorless and tasteless, or as nearly so as ma be desired. It is freed from moisture an then constitutes finished white oil of about eighty seconds, more or less, viscosity at 100 F., the yield being about sixty two, per cent of the white oil stock. Its-gravit should be appreciably less than that of sai stock, say a out 36.3 B. as a ainst 34 B.

The Florida clay may well be in piecessmall nough to ass through a sieve of thirty meshes to tie linear inch :and large enough to be caught by one with sixty meshes. It may be placed in one or more filtering vessels on cloth over rforated bottoms and can be used until tli: filtrate V s off in color (no longer yielding an oil w ich -is of the desired colorlessness. after steamuse; since in this way a substantial saving 180 neutralized) the distillate is collected separately so long as the com onenthydrocar- "bons are of an undesirably ow viscosity. In

acid er barrel of said stock) since the dein the mount of clay per barrel of oil can be made without loss in decolorizing effect. In other words,-it hasbeen discovered that the power of clay to remove one part of the coloringmatter ofviscous petroleum is retained and can be utilized after its power to attract another part thereof to itself has becomeexhausted, or practically so. \Vhile other modes are not excluded for carrying out this special improvement, what is considered best is to use say four filtering vessels, each five feet'in diameter and fourteen feet high, filled twelve feet deep with the clap, and to arrange for passing the oil through said vessels in series in such manner that the series can begin with any vessel and that any vessel can be cut out when desired. Useful arrangements for the purpose I are known in other connections. Starting say with three vessels in series and the fourth cut out and filled with fresh clay, when the filtrate tends to go off in color said fourth vessel is included asthe last in the series; and the first vessel of the series is cut out. This last mentioned vessel is then emptied and refilled. hen the filtrate again tends to go off in olor, the vessel is again includedinthe series, but this time at the tail end thereof. \Vhat was originally the sec- 0nd vessel of the series is cut out at the same time or when desired. And so filtration proceeds practically without interruption first through partially exhausted clay and then through that which is less and less ex liausted (if exhausted at all). Under the conditions mentioned about fifty five pounds of fresh clay'per barrel (40 gallons) of filtered oil have been found to give a water white oil appreciably less colored "than the dilute solution herein above mentioned of potassium ch'romate.

The steaming may well be performed under atmospheric pressure at a temperature of about 212 F. Thehot water of condensation washes out some impurities; and others (such as a little sulfur dioxid and some cracked hydrocarbons,- amounting to perhaps about one-half per cent. of the steamed oil) pass off in the current of uncondensed steam,

In obtaining products from petroleum instead of reducing (partially distilling) the crude petroleum for cylinder lubricating stock anddistillate as aforesaid, it is more commbn to distill the crude petroleum completely for distillate, only dry coke remaining as residue Suchcomplete distillation is usually performed without injection of a'eriform fluid into the oil in distillation, and is. therefore, accompanied with more docomposition (cracking) of component hydrocarbons than occurs in said-reduction for oil stockthan distillate of the same viscosity 35 from said reduction. If, necessary or expedient to utilize such inferior stock, however, it would be best to usedistillate obtained in reducing the pressed parafiin distillate in the customary manner for obtaining therefrom heavy lubricant stock (as residue) and other products as distillate), such reduction being performed with injection of dry steam into the oil. A cut of distillate may well be taken which would contain hydro carbons of the viscosities desired in the oil to be made; and further reduction or other distillation of said out can be performedif necessary-or expedient in order to secure stock of the desired viscosity.

The manner of operating upon such stock would not be so different from what has been already describedas to require further description.

Herein above injection of dry steam has been described as the best'mode of avoiding decomposition in distillation; iother modes are not necessarily excluded. Injection of other inert aeriform fluid also tends to do so. -Distillation under subatmospheric pressure, for example, might serve, especially if what would be considered in the art as a high vacuum should be employed. A partial vacuum could be .used with or without injection of dry steam or of other inert aeriform fluid.

\Vhile the invention relates primarily to making white oils from distillate from pctroleum of the Pennsylvania or similar type,

it is not necessarily limited exclusivelythereto. It is believed that it can usefully be applied tothe manufacture of white oils from distillate from petroleum of any other type. Less sulfuric acid and clay, it is believed, would be re uired for the manufacture of a white 011 of given viscosity from Russian than from Pennsylvania distillate. I

Crude petroleum .of the Pennsylvania type has a gravity which ranges between about 40 B. and about 45 13.; it has an amber color; it is suitable for themanufacture of cylinder lubricating stock by reduction with injection of dry steam; it contains paraffin wax in workable proportion; and it is comparatively free fromhydrocarbone of the aromatic (closed chain) series. Its component hydrocarbons of boiling points normal to burning oil (kerosene) (302 F. .to 572 F.) are lighter in gravity than the h drocarbons of the same boiling points in ussian petroleum. Any petroleum is considered to-be of a type similar to the Pennsylvania type in the particulars herein set forth when it possesses sufiicient of the properties mentioned to ally it to Pennsylvania rather than to Russian petroleum.

While the invention relates primarily to white oils, that is to say, ,to viscous oils which are water white'at least approxi- 1 mately in color; it is evident that viscous oils not water white in color even approximately could be made from viscous distillate by the described procedure usin suitably smaller amounts of one or ot er or of each of the decolorizing agents per barrel of oil subjected to them respectively;

' and such manufacture may well involve advantages over the prior state of the art, at

least for some purposes. .It is also believed that oils of non-petroleum ori but anal ogous thereto, such as shale oils. for exam- -ple, can be decoloiized in accordance with the invention to a.'usefu l extent; and the' decolorizing of hydrocarbon products not liquid at 60 F. under atmospheric pressure is not necessarily excluded from the scope of the invention. of the present specification is, therefore, p rimarily;but not exclusively, a product of ennsylvania or similar petroleum; it may be a product of petroleum of any other t pe; or it may beobtained from a material rendered notably lighter in color than the: stock whence derived; although it may not be approximately water white. Such decolorized hydrocarbon oil to be of viscous character must have a viscosity above fort seconds at 100$ F. y

e solid decolorizing material of the present specification is primaril but notexclusively, clay; it is also inten ed by said expression to cover other solid decolorizin material through which oil can be filtere I claim as my invention or'discovery:

1. The process of making. a decolorized hydrocarbon oil of viscous character, consisting in (1) sub'ecting stock'which has a viscosity above orty seconds at 100 'F. to the action of sulfuric acid so as to form an acid slud which is removed, (2) distilling the acid treated oil \with use of special agency to prevent the decomposition of component h drocarbons and so obtaining distillate w ich has a viscosit forty seconds at'100 R, (3) subjecting said distillate to the action of sulfuric acid so as to form an acid sludge which is removed, and (4) filtering the oil which has; thus been twice subjected to-sulfuric acid and-to an interveningdistillation throu h solid decolorizing material, substantia ly as described.

2. The process of making a 'decolorized hydrocarbon oil of viscous character consisting 1n (1) subjecting stock which has The hydrocarbon 011 above a viscosity above forty seconds at 100 F. and which has been obtained as distillate in a distillation with use of special agency to prevent decomposition of component hydrocarbons to the action of sulfuric acid so as to form an acid sludge which is removed, (2) distilling the acid treated oil .witli use of special agency to prevent the decomposition of component hydrocarbons and so obtaining distillate which has a viscosity aboveforty seconds at 100 F., (3) sub'ectin said distillate to the action of sul uric acid so as to form an acid sludge which is removed, and (4) filtering the oil which has thus been twice subjected to sulfuric acid and toan intervening distillation through solid decolorizing material, substantially as described.

3. The process of making a decoloi'ized hydrocarbon oil of viscous character, consisting in (1) subjecting stock which has a viscosity above forty seconds at 100 F. and which would be collectible as distillate within a range of not more than about ten degrees B. at the condenser outlet to the action of sulfuric acid so .as to form an acid sludge which is removed, (2) distilling the acid treated oilwith use of special agency to re- -vent the decomposition of component by rocarbons and so obtaining distillate which has'a viscosity above forty seconds at 100 F., (3) subjecting said distillate to the action of sulfuric acid so as to form an acid sludge which is removed, and (4) filtering the oil which has thus been twice subjected to sulfuric acid and to an intervening distillation through solid decolorizing material, substantially as described.

4; The process of making a decolorized hydrocarbon oil of viscous character. consisting in (1) sub'ccting stock which has a viscosit above orty seconds at 100 F. and whic would be collectible as distillate within a range of not more than about ten degrees B. at the condenser outlet to the action of sulfuric acid so as to form an acid sludge which is removed, (2) distilling the acid treated oil with use of special agency to prevent the decomposition of com nent hydrocarbons and with collection of t e major part but not of all the obtainable distillate and so obtaining distillate which has a viscosity above forty seconds at 100 F., (3) subjecting'said distillate to the action of sulfuric acid so as to form an acid sludge which is removed, and,(4) filteringthe oil which hasthus been twice subjected to sulfuric acid and to an intervening distillation through solid decolorizing material, substantially as described.

5. The process of making adecolorized hydrocarbon oil of viscous character, consisting inv (1) subjecting stock which has a viscosity above forty seconds at 100 F. and. not: more than a few seconds difierent from cosity above forty which contains the last that to be obtained in the decolorized oil to the action of sulfuric acid so as to form an acid sludge which is removed; (2) distilling the acid treated oil with use of special agency to prevent the decomposition of component hydrocarbons and so obtaining distillate which has a viscosity not more than a few seconds different from that of said stock, (3) subjecting said distillate to the action of sulfuric acid soas to form an acid sludgeavhich is removed, and (4) filterin the oil which to sulfuric, tillation through solid dccolorizing material, substantially as described.

(3. The process of making a decolorized hydrocarbon oil of viscous character, consisting in (1)subjecting stock which has a VISCOSltYnbUVe forty seconds at 100 F. and

whose most viscous hydrocarbons would be desirable in the decolorized oil to the action of sulfuric acid so as to form an acid sludge which is removed, (2) distilling the acid treated oil to at least approximate dryness with use of special agency to prevent the decomposition of'component h drocarbons and so obtaining distillate which has a visrunnings of said distillation, (3) subjecting said distillate to the action of sulfuric acid so as to form an acid sludge which is removed, and (4) filtering the oilwhich has thus been twice subjected 'to sulfuric acid and to an intervening distillation through solid decolorizing material, substantially as described.

7. The process of making a decolorized hydrocarbon oil of viscous character, con,- sisting in (1) subjecting stock which has a viscosity above forty seconds at 100 F. to the action of sulfuric acid so as to form an acid sludge which is removed, (2) distillin the acid treated oil with use of special agency to prevent the decomposition of component hydrocarbons and so obtaining distillate whichhas a viscosity above forty seconds at 100 F., (3) subjecting said distillate to the action of sulfuric acid so as to form ah acid sludge which is removed, and 1) filtering the pilwhich has thus been twice subjectedto sulfuric acid and to an intervening distillation through solid decolorizing material, sulfuric acid stronger than commercial acid of 1.835 specific gravity being employed in one at least of the treatments mentioned, substantially as de? scribed.

8. The process of making a decolorized hydrocarbon oil of viscous character, consisting in (1) subjecting stock which has aviscosity above forty seconds at 100 F. to the action of sulfuric acid so as to form an acidsludge which is removed, (2) distilling the acid treated oil withuse of special 0 has thus been twice subjected ac d and toan intervenmg dis-K seconds at 100 F. andagency to prevent the decomposition of component hydrocarbons'and so obtainlng dis tillate which has a viscosity above forty seconds at 100 1 (3) subjecting said distillate to the action of sulfuric acid so as to form an acid sludge which is removed, and (4) filtering the oil which has thus been twice subjected to sulfuric acid and to an intervening distillation through solid decolorizing material, the initial temperature for one at least of said treatments with sulfuric acid beingbetween 70 and 20 =1. and lower scribed.

9. The process of making a decolorized hydrocarbon oil of viscous character, consisting in (1) subjecting stock which has a viscosity above forty seconds at 100 F. to the action of sulfuric acid so as to form an acid sludge which is removed, (2) distilling the acid treated oil with use of special agency to prevent the decomposition of component hydrocarbons and so obtaining distillate which has a viscosity above forty seconds at 100 F (3) subjecting said distillate to the action of sulfuric acid so as to form an acid sludge which is removed, and

(4) filtering the oil which has thus been twice subjected to sulfuric acid and to an intervening distillation through solid -decolorizing material, the treatment with sulfuric acid which precedes said intervening distillation being more energetic than that which follows the same, substantially as described.

10.The improvement in distilling hydrocarbon oil of "iscous character with injection of aeriform fluid thereinto, consisting in making a number of runs which are performed with inject-ion of aeriform fluid into the oil in distillation and are carried to such extent only that a considerable percentage of each charge remains undistilled, accumulat-, ing this residual oil from an appropriate number of such runs, and completing the distillation of the so accumulated oil with injection of aeriform fluid thereinto until a condition of at least approximate dryness is attained, substantially as described.

11. The process of making a decolorized hydrocarbon oil of viscous character, consisting in (l) subjecting stock which has a viscosity above forty seconds at 100 F. to the action of sulfuric, acid so as to form an acid sludge which is removed, (2) distilling the acid treated oil with use of special agency to prevent the decomposition of component hydrocarbons and so obtaining distillate which has a viscosity above forty seconds at, 100 F., (3) subjecting said distillate to the action of sulfuric acid so as to if desired, substantially as deintervening distillation in acid condition through solid, decoIOriZing'materiaI, substantially as described. z 12. The process of making a decolorized hydrocarbon oil of viscous character, consisting in (1) sub'ecting stocknwhich has a viscosity above orty seconds at 100 F.

v to the action of sulfuric acid so as to form an acid sludge which is removed, (2) distilling the acid treated oil-with use of s ecial agency to prevent the decomposition 0 componenthydrocarbon's and so obtaining distillates which has a viscosity above forty seconds at 100 F., (3) subjecting said distillate tov the action of sulfuric acid so as to form an acid sludge which is removed, (4) filteringthe oil which has thus been twice subjected to sulfuric acid and to an intervening distillation through solid decolorizing material, and (5) washing the filtrate oil with hot water, substantially as described. 13..The process of making a decolorized viscosity above forty seconds .atf 10 0 F. to the action of sulfuric acid so aslto form an acid sludge which is removed, (2) distilling the acid treated oil with use of special agency to revent the decomposition of component hy rocarbons and so obtaining distillate which has a "iscosit above forty seconds at 100 F., (3) subjecting said distillate to the action of sulfuric acid so as to form an acid sludge which is removed, and (4) filterin the oil which has thus been twice subjected to sulfuric acid and to an intervening distillation through solid decolorizin material, sufiiciently ener tic treatments with sulfuric acid being emp oyed for the decolorized oil to be obtained with a proportion of solid decolorizing material equivalent in decolorizing power to not more than about three hundred pounds of 'fresh Florida clay per barrel of oil sub'ected to the filterin operation 85 i the case of an oil of about eig ty seconds viscosity at 100 F. and with corresponding hydrocarbon oil of viscous character, conincrease in the proportion of solid decolorizsisting in (1) subjecting stock which has a viscosity above forty seconds at 100 -F. to

the action of sulfurlc acid so as to form an acid sludge'kwhich is removed, (2) distilling the acid treated oil with use of special agency to revent the decomposition of component 80 hy rocarbons' and so obtaining distillate which has avviscosit above forty seconds at 100. F., (3) subjecting said distillate to the action of sulfuric acid so as to form an acid slud which is removed, (4) filterin the oil 85 whic has thus been twice subjecte to sulfhric acid and to an intervening distillation through solid decolorizin material, and (5) partially distilling the ltrate' oil with inection of aeriform fluid into the same, sub- 40 sta'ntially as described.

" 14; The process of making a decolorizedhydrocarbon oil of viscous. character; consisting in (1) subjecting stock which has a viscosity above forty seconds at 100 F. to

the action of sulfuric acid so as to form an acid sludge which is removed, (2) distilling the acid treated oil with use of s ia agency to prevent the decomposition 0 component hydrocarbons and so obtaining d1st llate which has a viscosity above forty seconds 'at- 100 F., (3) sub ecting said distil-c late to the action" of sul uric acid so as to' form an acid sludge which is removed, (4) filtering the oil which has thus been twice subjected to sulfuric acid and to an intervenmg distillation through solid decolorizing material, and (5) then injecting steam into the filtrate oil under such conditions of temperature and pressure that the steam will 6,0 in part condense in the oil and in part pass off in aeriform state, substantially as de-, scribed. c

15. The process of making a decolorized hydrocarbon .oil of viscous character, con- 66 sisting in (1) subjecting stockwhich has a 100 (3) subjecting said distillate to the .ing material for more viscousoil, substantially as described.

16.'The process of making a decolorized hydrocarbon oil of viscous character, consisting in (1) subjecting stock which has a viscosity above forty seconds at .F. to the action of sulfuric acid so as to form an acid sludge which is removed, (2) distilling the acid treated oil with use of special agency to prevent the decomposition of component by rocarbons and so obtaining distillate which has a'viscosit above forty seconds at action 'of sulfuric acid so as to form an acid sludge which is. removed, and (4) filterin the oil which has thus been twice subjected to sulfuric acid and to an intervening distil lation through solid decolorizing material, the total sulfuric acid being equivalent in content of sulfur trioxid to not more than about twenty gallons of 20% fuming sulfuric acid per barrel "of stock in the case of an oil of about eighty seconds viscosity at 100 F. and with correspondin increase in the proportion of sulfuric aci for more viscous oil, substantially as described. I

17. The process of making a decolorized hydrocarbon oil of viscous character, consisting in (1) subecting stock which has a viscosity above orty seconds at 100 F. to the action of sulfuric acid so as to form an acid sludge which is removed, (2) dis- 12,0 tilling the acid treated oil with use 0 s ial agency to prevent the decomposition 0 component h dro'carbonsand so obtaining distillate w 'ch has a viscosity above forty seconds at 100 F., (3) sub'ecting said dis- 126 tillate. to the action of sul ric acid so as to form an acid sludge which is removed, and (4) filtering the oil which has thus I been twice subjected to sulfuric acid and to an intervening distillation through solid de- 130 colorizing material, sufliciently energetic treatments with sulfuric acid being employed for the decolorized oil to be obtained with a proportion of solid decolorizingmaterial equivalent in decolorizing power to not more than about three hundred pounds of fresh Florida clay per barrel of oil subjected to the filtering operation and the total sulfuric acid being equivalent in content of sulfur trioxid .to not more than about twenty gallons of 20% fuming sulfuric acid per barrel of stock in the case of an oil of about eighty seconds viscosity at 100 F. and with corresponding increase of the solid decolorizing material and the sulfuric acid respectively in the case of more viscous oil, substantially as described.

18. The process of making a decolorized hydrocarbon oil of viscous character. consisting in (1) subjecting stock which has a. viscosity above forty seconds at 100. F. to the action of sulfuric acid which consists at least in part of sulfuric anhydrid. so as to .form an acid sludge which is removed, (2) distilling the acid treated oil with use of special agency to prevent the decomposition of component hydrocarbons and so obtaining distillate which has a viscosity above forty seconds at 100 F., (3) subjecting said distillate to the action of sulfuric acid so as to form an acid sludge which is removed. and (4) filtering the-oil which has thus been twice subjected to sulfuric acid and to an intervening distillation through solid decolorizing material. substantially as described.

19. The process of making a decolorized hydrocarbon oil of viscous character. consisting in (1) subjecting stock which has a viscosity above forty seconds at- 100 F., to the action of sulfuric acid which consists at least in part of sulfuric anhydrid. so as to form an acid sludge which is removed. (2) distilling the acid treated oil with use of special agency to (prevent the decomposition of component hy 'ocarbons and so obtaining distillate which has a viscosity above forty seconds at 100 F.. (3) subjecting said distillate to the action of sulfuric acid which consists at least in part of sulfuric anhydrid. so as to form an acid sludge which is removed, and (4) filtering the oil which has thus been twice subjected to sulfuric acid and to an intervening distillate through solid decolorizing material, substantially as described.

20. The process of making a decolorized hydrocarbon oil of viscous character. consisting in (1) subject-ing stock which has a viscosity above fort-y seconds at 100 F. to the actlon of sulfuric acid stronger than commercial acid of 1.835 specific gravity so as to form an acid sludge which is removed, (:2) subjecting the acid treated oil after neutralization with alkaline material to distillation with use of special agency to prevent the decomposition of componenthydrocarbons and so obtaining distillate which has a viscosity above forty seconds at 100 F., (3) subjecting said distillate to the action of sulfuric acid so as to form an acid sludge which is removed, and (4) filtering the oil which has thus been twice subjected to sulfuric acid and to an intervening distillation through solid decolorizing-material, substantially as described.

In testimony whereof I aflix my signature in presence of two witnesses ERNEST B. COBB. Witnesses: Y a

LOUISE Bonn,

F. J. Vaxoannn. 

